The invention relates to a method for fabricating a communications cable containing optical fibers.
Coaxial undersea communications cables have been manufactured for analog telecommunications systems. Those cables have been fabricated to withstand some obvious environmental factors such as low temperature, high compressive pressure and corrosive water. Additionally undersea cables have been made to withstand large tensile and bending stresses encountered during cable laying and recovery operations.
Recent advances in the field of optical fiber communications technology have made possible some practical optical fiber communciations systems. The characteristics of these systems, such as digital format, wide bandwidth and long repeater spacings, lead to what appears to be a relatively low cost per channel mile. This potential low cost makes an undersea communications cable containing optical fibers an attractive alternative to present day analog coaxial communications cables.
Heretofore, an undersea cable containing optical fibers was described in U.S. Pat. No. 4,156,104, issued to R. C. Mondello. Such cable included stranded steel wires separated from a central filament by a core in which the fibers are embedded.
A problem arises in the fabrication of a cable including optical fibers for use in an undersea communication system. The measured loss of the optical fibers included in the cable is dependent upon strain in the cable. Any large fluctuation in strain in the cable during manufacture, deployment, or operation of the cable system complicates the processes of starting up, lining up and operating the undersea communication system.